Both will work fine, and as far as the interface, each has it's easy and confusing points, IMO. I have both brands and kinda prefer the Yaesu's but it is probably becasue I have used them for so long. They do seem to be a bit more common in our small rally world in the US so getting help if you forget how to program it may be easier with the Yaesu. Have fun with it, Mike!
Another vote for the 2900. 2 of my 3 drivers have them installed in their rally cars, the other using an ICOM. I use the 2900 for course car work as well. The only downside to the Yaesu's is the need for the voltage dividing resistor when you're hooking up a ptt between the Peltor Amp and the radio.
Bruce Weinman alerted me to a Yaesu FT-2800M that appeared on Craigslist in MN and he checked it out, bought it, sent it to me and I sent him a PayPal "gift." The radio looks barely used so I'm stoked. Now I need an antennae ...
Halley (WB5SQC) ...
You'll also need an NMO mount (permanent roof, bracket or mag base) & some coax. I have thus far resisted the optimum solution of drilling a permanent hole in the roof (to make use of the roof as a nice ground plane) of my service rig, since I have a roof rack that I'd like to extend the full length of the roof, so I opted for half wave no ground plane antennas & semi-permanent NMO mount brackets bolted to the roof rack. I have also used mag mounts on occasion on ad hoc installs, but usually tie a loose knot in the coax to the roof rack, so in the event it does get knocked off, the mag mount stays attached to the vehicle.
Good drivers have dead flies on the side windows. - Walter Röhrl